Tissue-Specific mRNA Expression Profiles of Human Toll-Like Receptors and Related Genes

The mRNA expression levels of 10 toll-like receptors (TLRs) and 21 related genes in total RNA from pooled specimens of fetal human tissues (brain and liver), from single and pooled specimens of various adult human tissues (adrenal gland, brain, heart, kidney, liver, lung, placenta, prostate, salivary gland, skeletal muscle, small intestine, spinal cord, spleen, testis, thymus, thyroid gland, trachea, and uterus), and from two cell lines (Hep G2 and HeLa) were analyzed by real-time reverse transcription PCR. The mRNA expression of the 10 human TLRs was successfully detected in all of the tissues and in HeLa cells. TLR2, TLR3, TLR6, and TLR9 were consistently expressed in Hep G2 cells, but TLR1, TLR4, TLR5, TLR7, TLR8, and TLR10 showed no or very weak expression in these cells. The mRNA expression of many TLR-related genes (ICAM1, CD14, MyD88, LY96, TRIF, TICAM2, TIRAP, CD83, SOCS1, TNFAIP3, TOLLIP, IRAK1, IRAK2, IRAK4, and TRAF6) was successfully detected in all of the tissues and cell lines. The mRNA expression of CD80, CD86, IRAK3, and CCL2 was successfully detected in all of the tissues and cell lines except for Hep G2 cells. The mRNA expression of CCL5 was successfully detected in all of the tissues and cell lines except for fetal brain. The mRNA expression of CXCL10 was successfully detected in all of the tissues except for fetal and adult brain. These results provide valuable information for studies concerning the regulation of TLR-related genes.